I am not sure, but I hink it is C!
Answer:
-7
Step-by-step explanation:
You use the quadratic formula of
to get:
a = 1
b = 7
c = -13
then you plug that into x= (-b ± √b²-4ac)/(2a) :
x= ( -7 ± √7²- 4(1)(-13) )/(2(1))
![x=-\frac{7}{2} + \frac{\sqrt{101}}{2} \\\\x=-\frac{7}{2} - \frac{\sqrt{101}}{2}](https://tex.z-dn.net/?f=x%3D-%5Cfrac%7B7%7D%7B2%7D%20%2B%20%5Cfrac%7B%5Csqrt%7B101%7D%7D%7B2%7D%20%5C%5C%5C%5Cx%3D-%5Cfrac%7B7%7D%7B2%7D%20-%20%5Cfrac%7B%5Csqrt%7B101%7D%7D%7B2%7D)
The sum of these two x values turns out to be:
![x=-\frac{7}{2} + \frac{\sqrt{101}}{2}+( -\frac{7}{2} - \frac{\sqrt{101}}{2} )= -\frac{14}{2} = 7](https://tex.z-dn.net/?f=x%3D-%5Cfrac%7B7%7D%7B2%7D%20%2B%20%5Cfrac%7B%5Csqrt%7B101%7D%7D%7B2%7D%2B%28%20-%5Cfrac%7B7%7D%7B2%7D%20-%20%5Cfrac%7B%5Csqrt%7B101%7D%7D%7B2%7D%20%29%3D%20-%5Cfrac%7B14%7D%7B2%7D%20%3D%207)
Answer:
The answer is the option A
![\frac{1}{2}(\sqrt{[(y2)^{2}+(x2)^{2}]*[(y1)^{2}+(x1)^{2}]})](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%28%5Csqrt%7B%5B%28y2%29%5E%7B2%7D%2B%28x2%29%5E%7B2%7D%5D%2A%5B%28y1%29%5E%7B2%7D%2B%28x1%29%5E%7B2%7D%5D%7D%29)
Step-by-step explanation:
see the attached figure with letters to better understand the problem
we know that
The area of the triangle is equal to
![A=\frac{1}{2}bh](https://tex.z-dn.net/?f=A%3D%5Cfrac%7B1%7D%7B2%7Dbh)
where
b is the base
h is the height
In this problem
![b=AB, h=AC](https://tex.z-dn.net/?f=b%3DAB%2C%20h%3DAC)
the formula to calculate the distance between two points is equal to
Find the distance AB
![A(0,0), B(x2,y2)](https://tex.z-dn.net/?f=A%280%2C0%29%2C%20B%28x2%2Cy2%29)
substitute
Find the distance AC
![A(0,0), C(x1,y1)](https://tex.z-dn.net/?f=A%280%2C0%29%2C%20C%28x1%2Cy1%29)
substitute
Find the area of the triangle
we have
![b=\sqrt{(y2)^{2}+(x2)^{2}}, h=\sqrt{(y1)^{2}+(x1)^{2}}](https://tex.z-dn.net/?f=b%3D%5Csqrt%7B%28y2%29%5E%7B2%7D%2B%28x2%29%5E%7B2%7D%7D%2C%20h%3D%5Csqrt%7B%28y1%29%5E%7B2%7D%2B%28x1%29%5E%7B2%7D%7D)
substitute
![A=\frac{1}{2}(\sqrt{[(y2)^{2}+(x2)^{2}]*[(y1)^{2}+(x1)^{2}]})](https://tex.z-dn.net/?f=A%3D%5Cfrac%7B1%7D%7B2%7D%28%5Csqrt%7B%5B%28y2%29%5E%7B2%7D%2B%28x2%29%5E%7B2%7D%5D%2A%5B%28y1%29%5E%7B2%7D%2B%28x1%29%5E%7B2%7D%5D%7D%29)
Answer:
v=52.5
Step-by-step explanation:
the angle is right so both of the sides should equal 90 degrees
90-(minus)37.5 is 52.5